1. Field of the Invention
This invention relates to dust sealing covers, or balloon or boot seals as commonly called, for pivotal ball joints for use in automotive steering linkages, wheel suspensions or other linkage systems.
2. Description of the Prior Art
The ball stud of a pivotal ball joint assembly is generally designed for full pivotal movement relative to a socket housing having an open end through which the ball stud protrudes. Accordingly, it is important that a dust sealing cover fitted over the open end of the housing for preventing the ingress of foreign matter, dust or the like into the interior of the ball joint be elastically deformable to adapt itself to the pivotal movement of the ball stud, and yet, can be securely held on the housing and the ball stud when it is deformed. In order to satisfy these requirements, it is ordinary practice to provide the dust sealing cover with a thin-walled middle portion, or form an annular groove on that portion of the housing on which the cover is fitted at one end thereof having a reduced diameter adapted for press fitting in the annular groove of the housing.
The dust sealing cover having such a thin-walled middle portion is effectively used on a ball joint employed for applications in which its ball stud is not very frequently liable to pivotal movement, because the thin-walled middle portion is elastically deformed in response to the pivotal movement of the ball stud. The dust sealing cover having its reduced diameter end press fitted in the annular groove on the housing can be maintained in a firmly secured position relative to the housing, and finds effective application in uses in which the time and labor required for fitting the cover do not present any substantial problem.